July 3, 2006

Atrial fibrillation on the rise in US: researchers

WASHINGTON (Reuters) - The number of people with a
dangerous heart arrhythmia is higher than previously estimated
and increasing, researchers reported on Monday.

In a study of Minnesota residents, the incidence of atrial
fibrillation rose more than 12 percent between 1980 and 2000,
the researchers said.

At that rate, the number of U.S. residents with the rhythm
will rise to 16 million by 2050 -- nearly three times previous
estimates, they added.

"This is a major problem for our country," said Dr. Teresa
Tsang, senior author of the study to be published in
Circulation: Journal of The American Heart Association. "Unless
we are able to prevent atrial fibrillation, it will exact a
major toll on our healthcare resources in the coming years."

Atrial fibrillation is a condition in which the heart's
upper chambers quiver instead of beating regularly. This
arrhythmia increases the risk of stroke, heart failure,
cognitive impairment and death.

Many people do not experience heart palpitations, shortness
of breath or other symptoms that would bring the condition to
the attention of a health care provider, Tsang explained.

Scientists do not know the cause of the condition, but its
risk factors include high blood pressure, diabetes, and
valvular heart disease. Recent data have also indicated that
obesity is a risk.

The rise in U.S. obesity mirrored the rise in the
arrhythmia and might explain 60 percent of the new cases in
Tsang's study, she said.

Researchers identified more than 4,500 adults in Olmsted
County, Minnesota whose medical records showed at least one
incidence of atrial fibrillation and confirmed its presence
with an electrocardiogram.

Based on this data, the study estimated that 5.1 million
Americans currently live with the condition. That's nearly
twice as many as estimated by other studies, which have
examined patients in health maintenance organizations only.

"Even with this number, we still believe that we're
underestimating the prevalence," Tsang said.